A.misalignment or worn main bearings
B.insufficient cylinder lubrication
C.defective or poorly fitted valves
D.all of the above
您可能感興趣的試卷
你可能感興趣的試題
A.They make it easier to replace the pump shaft packing
B.They can be economically replaced as they wear out
C.They can be removed when it is necessary to lighten the weight of the pump
D.They increase the strength of the shaft
A.superheated
B.saturated
C.condensed
D.convected
A.radially from the shaft
B.parallel to each other and to the shaft
C.parallel to each other but at a right angle to the shaft
D.at an angle to each other and to the shaft
A.3 or 5
B.5 or 7
C.7 or 9
D.9 or 11
A.sensible heat
B.latent heat
C.total heat
D.residual heat
最新試題
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
A grease gun is generally used to lubricate a （）.
A salinity indicator is used to determine the （）.
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.
If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.
The general purpose of a heat exchanger is to （）.
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.
One cause of high head pressure occurring in a refrigeration system can be （）.
On tank vessels equipped with power operated cargo tank valves, the type of power operator most commonly used is （）.